We've added this to the jam page:
"Games should be submitted as .zip archives (with an index.html and all files needed to run the game) and as a link to a playable version of your game with Web Monetization enabled on the page. We are unfortunately not able to use itch.io to host the playable games as itch.io loads HTML5 games in an iframe which prevents a Web Monetization enabled browser from detecting the payment pointer and your game from detecting a paying player."